Electric incandescent lamp and similar device



Sept. 10, 1935. H, ASMUS EN 2,014,220

ELECTRIC INCANDESCENT LAMP AND SIMILAR DEVICE Filed May 28, 1934 fNI ENTUR H'EIN JE'HAE UE SEN BY mM-U;

-.H s AT TURKEY Patented Sept. 10, 1935 UNITED STATES PATENT OFFICE.

DEVICE Heinrich Asmussen, Berlin-Steglitz, Germany, assignor to General Electric Company, a -cor-' poration of New York Application May 28, 193%, Serial No. 728,007 In Germany June 2, 1933 5 Claims. (Cl. 176-32) My invention relates to electric incandescent lamps and similar devices comprising a bulb having an electric energy translation element such as a filament sealed therein and a base mounted on said bulb. More particularly my invention relates to the bases for such devices and still more particularly to so-called mechanical bases in which the usual cement which unites the base to the glass bulb is eliminated.

- Mechanical bases proposed heretofore have been objectionable because they necessitated a comparatively complicated structure of the base shell or bulb. One of the objects of the present invention is to provide a base which is firmly secured to the neck of the bulb without the use of cement and is of comparatively simple design.

,According to my invention, the neck of the bulb is provided with longitudinal engagement means, preferably one or more grooves, which are engaged by corresponding engagement means in the base shell, preferably indentations therein, thereby preventing the said base shell from, rotating on the said bulb neck. The base shell is held on the bulb neck solely by means of a leading-in wire having high tensile strength, said wire being per leading-in wires are approximately .30 to .35

mm. indiameter. Such wires are comparatively soft and have low tensile strength, so that they were never stretched tightly heretofore because of the danger of breakage. However, this danger is obviated if a lead wlre,'for example of copper, having a comparatively large diameter, is used, or if a metal or alloy wire of standard diameter but having a high tensile strength, is used. For instance, a copper wire'of .50 mm. diameter or over maybe used without fear of breakage, or leads of the usual diameter, 1. e., .30 mm. may be used when made of, for example, beryllium-bronze, phosphor-bronze or steel. Such wires, when tightly'stretched between the stem press and the end of the base, hold the said base firmly on the neck of the bulb and prevent any movement thereof longitudinally of the bulb.

For a further understanding of the invention, reference may be had to the appended drawing in which Fig. l is an elevation, partly in section, of an incandescent lamp having a base structure comprising my invention; Fig. 2 is an elevation of the base at rightangles toFig. 1; and Figs. 3 and 4 are respective similar views of a modified base structure.

press portion ll 01' a stem tube [5.

Referring to Fig. 1, the lamp comprises a bulb l having a filament H sealed-therein and supported on wires i2 the ends of whicharc sealed in the end of an arbor i3 which extends from the The cylindri- 5 cal neck l6 of the bulb is provided with a pair of longitudinal grooves ii. A base comprising a screw threaded shell l8, insulation i9 and an eyelet 20 surrounds said neck portion of said bulb. The shell i8 has a. pair of indentations 2| therein 10 which engage with the grooves I1 and prevent rotation of said shell with respect to the-bulb. A pair of leading-in'wires 22-23 having portions thereof sealed in the stem press I are connected at their inner ends to the ends of the filament Ii. The leading-in wire 22 is bent over the neck of the bulb, placed in one of the grooves "and bent over the edge of the shell l8, the end thereof being soldered in the corresponding indentation 2i.

The said leading-in wire 22 maybe of the usual diameter of .30 to .35 mm., but the leading-in wire 23 is of greater diameter, preferably greater than .50 mm., for example, -.60 to .80 mm. Said leading-in wire 23 is secured to the end of the, base, preferably by solder 24 which forms an end 25 contact, and isstretched tightly between the said end of the base and the stem-press M, thereby securely holding the said base on the neck of the bulb.

In the species shown in Figs. 3 and 4 the neck of the bulb is provided with screw threads 25 formed therein. 'The base consists of a cap comprising a metal shell or ring 28, insulation 21 and an eyelet 28. The shell 28 has a pair of indentations 29 therein which engage with longitudinal grooves 30 in the bulb neck to prevent relative rotation of the said shell and bulb neck. *The lead wire 23 is soldered at II to the eyelet 28 in the same manner as in Figs. 1 and 2.

The invention is of course also applicable to 40 other sealed devices such as radio tubes, are lamps and electrical discharge devices.

What I claim as newand desire to secure by Letters Patent 01 the United States is: I 1. Anelectrical device comprising a bulb having a neck portion and a base comprising a metal shell surrounding said bulb neck and an end contact, said bulb neck and base shell having interlocking engagement means therein for preventing relative rotation therebetween, and a lead ing-in wire having a portion thereof sealed in a portion of. said bulb and an end thereof secured fixedly to said base end contact, said leading-in wire being tightly stretched between said bulb and base and constituting the sole means for holding said base firmly on said bulb neck against longitudinal displacement.

2. An electrical. device comprising a bulb having a neck portion and a base comprising a metal shell surrounding said bulb neck and an end contact, said bulb neck having a longitudinal groove therein and said base shell having an indentation therein engaging with said groove for preventing relative rotation between said base and bulb, and a leading-in wire having a portion thereof sealed in a portion of said bulb; and an end thereof secured fixedly to said base end contact, said leading-in wire being tightly stretchedbe'tween said bulb and said base and constituting the sole means for holding said base firmly on said bulb neck against longitudinal displacement.

3. An electrical device comprising a bulb having a neck portion and a base comprising an end contact and a metal shell surrounding said bulb neck and having screw threads formed therein, said bulb neck having a longitudinal groove therein and said base shell having an indentahaving a neck portion having screw threads formed therein and a base comprising an end ter-' minal contact and a metal shell constituting a second terminal contact surrounding a portion ofsaid bulb neck, saidbulb neck having a longitudinal groove therein and said base shell having an indentation therein engaging with said groove for preventing relative rotation between said base and bulb, a leading-in wire electrically connected to said base shell and asecond leading- 10 in wire having a portion thereof sealed in a portion of said bulb and an end thereof secured fixedly to said base end contact, said leading-in wire being tightly stretched between said'bulb and said base and constituting the sole means 1 for holding said base firmly on said bulb neck against longitudinal displacement.

5. An electrical device comprising a bulb having a neck portion and a base comprising a metal shell surrounding said bulb neck and a single end 20 contact, said bulb neck and base shell having interlocking engagement means therein 2 for, preventing relative rotation therebetween,- and a leading-in wire having a portion thereof sealed in a portion of said bulb and an end thereof secured fixedly tos'aid base end contact, said leading-in wire being tightly stretched between said bulb and base and constituting the-sole means for holding said base firmly onsaidbulb neck against longitudinal displacement.

' HEINRICH ASMUSSEN. 

